In the era of big-data, data communications between devices become more and more frequent. Conventionally, if data are to be sent in a device, they are required to be passed to a network layer from an application layer in that device. Once the data reach the network layer, at least a communication feature of the device is activated. Thus, the device is switched to an active mode, and the data are sent to other devices via networks immediately. After sending all the data from the application layer, at least the communication feature of the device is shut down, and the device is switched to an inactive mode. In the inactive mode, no data will be sent to other devices. Such a scheme requires frequent switches between the active mode and the inactive mode, so that a large amount of signaling and power consumption will be caused.
However, some communication devices may need to work continuously for a very long time period without recharging power. For example, measuring devices, sensors, fire alarm devices, indoor or outdoor security monitors, etc., are required to work for several months or even years. Moreover, these communication devices are designed to collect data frequently, but it's not necessary for them to frequently send out the collected data. Therefore, for these communication devices, power saving is required, and frequent activation of the communication feature would better be avoided.